Image processing apparatus, alignment method and storage medium

Patent metadata

Field	Value
Publication number	US-2019073779-A1
Application number	US-201816122234-A
Country	US
Kind code	A1
Filing date	Sep 5, 2018
Priority date	Sep 7, 2017
Publication date	Mar 7, 2019
Grant date	—

Abstract

An image processing apparatus includes first alignment means configured to perform an alignment in a horizontal direction on a plurality of two-dimensional tomographic images based on measurement light controlled to scan an identical position of an eye according to a first method, and second alignment means configured to perform an alignment in a depth direction on the plurality of two-dimensional tomographic images according to a second method that is different from the first method.

First claim

What is claimed is:

1 . An image processing apparatus comprising:
a first alignment unit configured to perform an alignment in a horizontal direction on a plurality of two-dimensional tomographic images according to a first method, the plurality of two-dimensional tomographic images being obtained based on measurement light controlled to scan an identical position of an eye; and a second alignment unit configured to perform an alignment in a depth direction on the plurality of two-dimensional tomographic images according to a second method that is different from the first method.

2 . The image processing apparatus according to claim 1 , wherein the first alignment unit performs the alignment in the horizontal direction on the plurality of two-dimensional tomographic images based on a positional deviation amount acquired by comparing projected images in the depth direction generated from the plurality of two-dimensional tomographic images according to the first method.

3 . The image processing apparatus according to claim 1 , wherein the second alignment unit performs the alignment in the depth direction on the plurality of two-dimensional tomographic images based on a positional deviation amount acquired by comparing layer boundaries detected from the plurality of two-dimensional tomographic images according to the second method.

4 . The image processing apparatus according to claim 3 , wherein the second alignment unit performs the alignment in the depth direction on the plurality of two-dimensional tomographic images based on a positional deviation amount of the layer boundary acquired from each of a plurality of regions dividing the two-dimensional tomographic image in the horizontal direction according to the second method.

5 . The image processing apparatus according to claim 4 , wherein the second alignment unit selects a predetermined number of positional deviation amounts from positional deviation amounts of a plurality of the layer boundaries in the plurality of regions such that a value indicating a variation of the positional deviation amount in the predetermined number of combinations is at a minimum, and performs the alignment in the depth direction on the plurality of two-dimensional tomographic images based on a representative value of the selected positional deviation amounts, according to the second method.

6 . The image processing apparatus according to claim 5 ,
wherein the value indicating a variation includes a variance or a standard deviation; and wherein the representative value includes an average value or a median value.

7 . The image processing apparatus according to claim 1 , further comprising:
an image selection unit configured to select a reference image being a reference for an alignment from the plurality of two-dimensional tomographic images, wherein the image selection unit selects the reference image based on at least one of a result of a comparison between projected images in the depth direction acquired from the plurality of two-dimensional tomographic images and a result of a comparison between layer boundaries acquired from the plurality of two-dimensional tomographic images.

8 . The image processing apparatus according to claim 7 ,
wherein the result of the comparison between projected images in the depth direction acquired from the plurality of two-dimensional tomographic images includes a similarity between the projected images; and wherein the result of the comparison between layer boundaries acquired from the plurality of two-dimensional tomographic images includes a positional deviation amount of the layer boundaries.

9 . The image processing apparatus according to claim 8 , wherein the image selection unit selects the reference image based on, in a case where one two-dimensional tomographic image and a plurality of other two-dimensional tomographic images are compared in the plurality of two-dimensional tomographic images, one of a number of two-dimensional tomographic images having a predetermined threshold or higher value of the similarity and having a predetermined threshold or lower positional deviation amounts of the layer boundaries and a number of two-dimensional tomographic images having a predetermined or higher number of regions dividing each of the two-dimensional tomographic images in the horizontal direction, the regions having a predetermined threshold or lower positional deviation amounts of the layer boundaries.

10 . The image processing apparatus according to claim 7 , further comprising:
a third alignment unit configured to perform an alignment on the plurality of two-dimensional tomographic images having undergone the alignment by the first alignment unit and the second alignment unit with reference to the reference image; and an image selection unit configured to select a reference image for the alignment to be performed by the third alignment unit from the plurality of two-dimensional tomographic images.

11 . The image processing apparatus according to claim 10 , further comprising a generation unit configured to generate an averaged image by averaging the plurality of two-dimensional tomographic images having undergone an alignment by the third alignment unit.

12 . The image processing apparatus according to claim 10 , wherein an OCTA image is generated from the plurality of two-dimensional tomographic images having undergone an alignment by the third alignment unit.

13 . An alignment method comprising:
performing an alignment in a horizontal direction on a plurality of two-dimensional tomographic images according to a first method, the plurality of two-dimensional tomographic images being obtained based on measurement light controlled to scan an identical position of an eye; and performing an alignment in a depth direction on the plurality of two-dimensional tomographic images according to a second method that is different from the first method.

14 . A non-transitory computer-readable storage medium storing a program for causing a computer to execute the method according to claim 13 .

Assignees

• Canon Kk

Inventors

• Iwase Yoshihiko
• Sagano Osamu
• Sato Makoto
• Uchida Hiroki

Classifications

• G06T7/0012

  Biomedical image inspection · CPC title

• G06T7/337 Primary

  involving reference images or patches · CPC title

• G06T2207/30041

  Eye; Retina; Ophthalmic · CPC title

• G06T2207/10101

  Optical tomography; Optical coherence tomography [OCT] · CPC title

• G06T3/0068

  Physics · mapped topic